Knife sharpener



Feb. 10. 192.5.

Mv T. G RAF KNIFE SHARPENER Filed April l5 1924 not perfectly Patented tee. in, 192

stairs stares MARTIN T. GRAF, F BUFFALO, NEW YORK.

KNIFE SHARPENER.

Application filed April 15,

1 0 all whom it may concern:

Be it known that I, llfARTiN T. Gear, a citizen of the United States, residing at Buffalo, in the county of Erie and State of New York, have invented a new and use- 7 ful Improvement in Knife Sharpeners, of

which the following is a specification.

This invention relates to a knife sharpener having a pair of sharpening disks and has for its object the production of a sharpener of this character which is simple in construction, which will notchatter while in use, which permits of reliably holding the disks against movement in case the same are flat, which permits of readily centering and assembling the disks On the bracket, and in which the disks are so constructed that the same are not brittle and liable to crack or break.

In the accompanying drawings Figure 1 is a perspective view of my improved knife sharpener, showing the same in use. Figure 2 is a side elevation thereof, on an enlarged scale. Figure 3 is a transverse section of the same taken on line 3l-3, Fig. 2. Figure l is a plan view of the sharpener detached from its support. Figure 5 is a vertical longitudinal section taken on the correspondingly numbered line in Figure 4.

Similar characters of reference indicate like parts throughout the several views.

In its general organization this knife sharpener comprises a bracket and two sharpening disks 11 mounted edge to edge on the'bracket so that upon drawing a knife 12 with its edge through the notch formed between the opposing edge portions of the disks the knife edge will be sharpened. This bracket in its preferred form has a base 13 which may be secured by screws 14 or otherwise to a support 15 of any suitable character, such for instance as a board, a table top, wall or the like. Projecting upwardly from the rear end of this baseis a standard 16 which inclines rearwardly and is provided on its front side with a rearwardly inclined flat face 17 upon which the rear flat sides of the sharpening disks rest in a rearwardly inclined position with their peripheral edge portions engaging or nearly engaging each other. The disks are detachably connected with the standard so as to be removable thereon, also adjusted toward each other, also rotated to bring different parts of their peripheries to the working 1924. Serial No. 706,702.

position and also permit of reversing the disks so as to enable both peripheral corners of each disk to be used and thus prolong the utility of the sharpener. The fastening means for this purpose preferably comprise washers 18 engaging with the front fiat sides of the sharpening disks and fastening screws each passing through openings 19, 20 in each companion washer and disk and engaging the threaded rear end of its shank 21 with a correspondingly threaded opening in the standard while its head 22 bears against the front side of the respective washer. The opening in'each disk is somewhat larger in diameter than the screw shank passing through the same in order to permit the disks to be readily moved laterally with reference to the fastening screws for bringing the peripheries of these disks into the desired working position.

It has been found in practice that when the standard is made comparatively thin at its lower end that the bracket is liable to vibrate or chatter upon drawing a knife between the disks and thus produce an unpleasant feeling and disagreeable noise. This is obviated by providing the standard with a rear inclined side 23 which is more nearly vertical than the front side of the standard, whereby the front and rear sides of the same converge upwardly and produce a standard having greater thickness at its lower end which rests on the base than the upper part thereof which carries the sharpening disks.

When the disks are manufactured the same are liable to be warped somewhat during the tempering operation and when thus distorted it is diflicult to clamp the same in place between the washers and the standard of the bracket and prevent the same from turning owing to the reduced contact between the disks and the standard. To overcome this difficulty the standard is provided on its face with recesses 24L opposite the central parts of the disks so that only the marginal parts of the disks engage with the standard, and as these marginal parts present the maximum surface area and are also farthest from the axes of the disks it is possible to hold the latter against turn ing by the pressure of the screws and thus ensure satisfactory operation of the sharpener.

Sharpening disks, when tempered so that they are of the same degree of hardness throughout and present sharp cutting cor- 11ers thereon, are liable to break when in use or when clamped on the bracket. To overcome this the disks in the present case are so tempered or treated that only the peripheral portions of the same are hardened while the central parts thereof are inade relatively soft. It follows'from this that when fastening the disks to the standard and when drawing ,a knife between the same for sharpening purposes the, soft center of thedisjks will; give suii'icicntly to, prevent breakage while the hard periphery of the same will maintain hard corners and operate effectively to sharpen a knife drawn past the same.

V For the purpose of permitting the disks to be. easily, quickly and. conveniently. assembled with the standard the front side, of the latter is provided at. the lower. end of the front face with a horizontal transverse edge, shelf, rib or shoulder, 25 upon which the lower edge portions of the disks are adapted to rest, andfthe standard is also provided on opposite sides of its frontface with forwardly projecting retaining lugs 26 which are adapted to engage with the opposite outer edges of thedisks. The distance betWQen. the lugs is preferably equal to the coinbined diameter of the disks. Upon therefore simply depositing the two disks upon the shelf between the two retaining lugs the disks center themselves automatically by gravity inasmuch as the same occupy practically the entire space between the lugs above the shelf and as the front face of. the standard inclines backwardly there is no tendencyfor thedisks to fall off from the standard after being deposited thereon, thereby avoiding 'displacement of the disks and permitting of readily. fastening the same by means of screws to'the standard.

edge portions engage with each other and form a good sharpening notch between them.

By arranging the Standard in an inclined position this serves to always ensure drawing the knife in the proper direction between the disks and it also permits of operating the sharpener in the most effective ensures en a in "the knife ed e with the u o b o a per front edges of the disks at the proper anglein which the. disks operate most effectlYely for sharpening the kn fe and. also enabling the operator to hold the knife in the most natural position while doing this work.

I claim asiny invention 1. A knife sharpener comprising a brac rot having. a. base, a standard rising from said base, a pair of parallel screw threaded. openings and recesses arranged on the rearside of. a standard, one around each threaded openin sharpening disks. engaging with the rear side ofv said standard and each arranged, with its central part over one ofsaid threaded openings and the respective recess, and. fastening screws passing through said disks and recesses and engaging said threaded openings.

2. knife sharpener comprising a bracket having a base, a. standard rising froinsaid base and having an upwardly facinginclined rear side, a horizontal shelf arranged transversely on the. lower part of said rear side and upright retaining lugs arranged on. said rear side at opposite ends of said shelf, a pair of sharpening disks resting with their.corresponding flat sides against said rear side ofthe standard and each disk. engaging the lower part of its periphery against said shelf and the outer part of its periphery against the inner side of one of saidretaining lugs, and fastening screws connecting said disks with said standard.

In testimony whereof I afiix my signature.

MARTIN T. GRAF.

A. a k 

